1. Field of the Invention
The present invention relates to a display device, and more particularly to a flat panel display and a fabricating method thereof.
2. Description of the Related Art
A liquid crystal display (LCD) device controls the light transmittance of a liquid crystal that has a dielectric anisotropy by use of an electric field, thereby displaying a picture. The LCD device includes a liquid crystal panel having a pixel matrix and a drive circuit for driving the liquid crystal panel. FIG. 1 is a block diagram illustrating an LCD device of the related art. As shown in FIG. 1, a related art LCD device includes a liquid crystal panel 10 having a pixel matrix, a gate driver 12 for driving a gate line 2 of the liquid crystal panel 10, a data driver 14 for driving a data line of the liquid crystal panel 10, and a timing controller 16 for controlling the gate driver 12 and the data driver 14. The liquid crystal panel 10 includes a pixel matrix having a thin film transistor 6, which is formed adjacent to the crossing of a gate line 2 and a data line 4. Likewise, an organic electro-luminescence device (OLED) includes a pixel matrix having a thin film transistor, which is formed adjacent to the crossing of a gate line and a data line. Each of the pixels includes a liquid crystal cell Clc that controls a light transmission amount in accordance with a data signal through a thin film transistor 6, which drives the liquid crystal cell Clc.
The thin film transistor 6 supplies a data signal from the data line 4 to the liquid crystal cell Clc in response to a scan signal of the gate line 2. The liquid crystal cell Clc makes the arrangement of the liquid crystal molecules change in accordance with the data signal, thereby realizing gray levels. The gate driver 14 sequentially supplies the scan signal to the gate line 2 in response to a control signal from the timing controller 18. The data driver 16 converts a digital data from the timing controller 18 into an analog data signal and supplies the analog signal to the data line 4. The timing controller 18 supplies the control signal which controls the gate driver 14 and the data driver 16, and also supplies the digital data to the data driver 16.
FIG. 2 is a plan view of a thin film transistor and a signal line included in a thin film transistor array substrate of the LCD device shown in FIG. 1. FIG. 3 is a cross-sectional view of a thin film transistor array substrate shown in FIG. 2 along I-I′. Referring to FIGS. 2 and 3, the thin film transistor 6 includes a gate electrode 26 connected to the gate line 2, a source electrode 22 connected to the data line 4 and a drain electrode 24 connected to the pixel electrode 28.
The thin film transistor 6, the signal lines, such as the gate line 2 and the data line 4, and a pixel electrode 28, are formed through mask processes that include photolithography, etching and cleaning processes. The gate line 2 and the gate electrode 26 are made of aluminum, such as AlNd, or copper. A low resistance metal, such as copper, is used if low resistance is desired. However, when the gate line 2 and the gate electrode 26 are made, conductive particles can be caught on the upper surface of the gate electrode 26 or gate line 2. For example, copper particles can be caught on the upper surface of a copper gate line from the fabrication of the copper gate line. Copper particles are harder to clean from an upper surface than other types of metallic particles.
A gate insulating film 3 of SiNx and a semiconductor layer 35 is formed on the upper surface of the gate electrode 26 and the gate line 2. The gate insulating film 3 of SiNx insulates the gate line 2 and the gate electrode 26 from the data line 4. The conductive particles from the fabrication of the gate line 2 and the gate electrode 26 may penetrate the SiNx and the semiconductor layer 35. Due to the spread or diffusion of the conductive particles, a short circuit can be generated between the gate line 2 and the data line 4, as shown in part A of FIGS. 2 and 3, and/or a short circuit can be generated between the gate electrode 26 and the source electrode 22, as shown in part B of FIGS. 2 and 3. The short circuit at part A causes abnormal driving of the gate line 2 so as to generate a black vertical line in a completed LCD device. The short circuit at part B shorts the source electrode 22 to the drain electrode 24, which causes a pixel to be a constant white spot in the panel of the LCD device. Typically, such a short circuit at B between the source electrode 22 and drain electrode 24 is broken by irradiation of laser to make the pixel a dark spot rather than a white spot. Such defects deteriorate the mass production yield and productivity of the LCD device. To reduce the generation of these short circuits, a plurality of cleaning processes for removing conductive particles are performed after formation of the gate line 2 and the gate electrode 26. These additional cleaning processes create another problem in that the fabricating process of the LCD device is more complicated and fabrication time is increased.